28 
BATHYMETRICAL SURVEY OF 
places a steep off-shore slope is indicated by the soundings, as, for instance, 
off the western shore of the longer arm towards the southern end, where 
a sounding in 55 feet was taken about 40 feet from shore, and a little 
farther north off the same shore, where a sounding in 24 feet was taken 
about 30 feet from shore ; again, off the western shore of the shorter arm, 
towards the northern end, a sounding in 57 feet was taken about 60 feet 
from shore. The approximate areas between the consecutive contour -lines, 
and the percentages to the total area of the loch, are as follows : — 
Feet. 
Acres. 
Per cent. 
Oto 25 
... 
265 
42 
25 „ 50 
183 
29 
50 „ 75 
... 
146 
23 
75 „ 100 
... 
33 
5 
Over 100 
... 
5 
632 
1 
100 
These figures show that the deep water is not of great extent, more 
than 70 per cent, of the lake-floor being covered by less than 50 feet of 
water, and more than 40 per cent, by less than 25 feet of water. 
Temperature Observations . — The following serial temperatures were 
taken in the deepest part of the loch, at 4 p.m., on September 6, 1902 : — 
Surface ... 
25 feet ... 
50 „ ... 
100 „ ... 
56°*1 Fahr. 
55°-6 „ 
55°-3 „ 
54°-7 „ 
These observations show a range of only 1°*4 throughout the 100 feet 
of water. 
Seiche . — A seiche was observed at the west end of the loch, having an 
amplitude of three-sixteenths of an inch, but the period could not be 
determined. 
Loch na Claise Fearna (see Plate X.). — Loch na Claise Fearna is 
a little irregular loch lying about half a mile from the southern shore 
of Loch Laxford, into which its outflow is carried by the Allt na Claise 
Fearna. It is about midway between Laxford Bridge and Scourie, the 
road skirting its eastern shore. In outline it is subtriangular, with the 
apex pointing in a north-east direction, and covers an area of about 
34 acres, while the area draining into it is nearly 2| square miles. The 
maximum depth of 38 feet was observed near the middle of the loch, 
between the large central island and the northern shore. The volume 
of water is estimated at 20 million cubic feet, and the mean depth at 
13 I feet. The loch was surveyed on Sej)tember 10, 1902, when the 
elevation of the lake-surface was found to be 135*0 feet above the sea. The 
western and southern parts of the loch are shallow, the deeper portion 
(exceeding 20 feet in depth) lying to the north and east of the large 
central island, and covering an area of about 6 acres, or 1 7 per cent, of the 
total area of the loch. 
